A LR35A nosewheel strut deflated after takeoff causing the nosewheel to retract turned thus preventing a safe nose gear up indication in flight. An emergency was declared followed by a normal landing at a diversion airport with lear maintenance.

On takeoff roll; a steering anomaly was encountered and the takeoff was aborted. Another attempt was made ending in an aborted takeoff. The passenger was dropped in the FBO and I inspected the nose gear and noticed no abnormality. The other pilot has more experience in type and we decided to request a high speed taxi on runway. The test produced no abnormality. We picked up our passenger and departed with no indication of malfunction. The right seat pilot performed the takeoff. During climb; we retracted the gear and noticed an unsafe light for the nose gear. We recycled several times and each time the gear locked down with 3 green lights and no red lights. After reaching a safe altitude; we declared an emergency and elected to land at ZZZ although our takeoff alternate was ZZZ2. We made that decision because there is a lear service center at ZZZ. The flight was uneventful. We encountered light rime ice during the flight. Upon arrival at ZZZ; we performed a low approach and the tower said the gear 'appeared down.' this was only a precautionary measure because we had 3 green lights indicating that all wheels were down and locked. We held the nose off the runway as long as possible and upon contact we felt a slight jerk to the left. The landing was normal otherwise. We engaged the electric steering and taxied to the ramp with no issues. The tower declined to have us write a report and the only information taken was by the fire crew. Upon inspection; the nose strut was found to be completely deflated. During preflight in ZZZ1; the nose strut was inflated within limits. The maintenance crew determined that the loss of directional control was due to the low strut and the red unsafe indication was due to the nosewheel being wedged at an angle in the wheel well not allowing the nose doors to completely close. Given the nature of the problem; I do not believe that we could have forecast the results we had supplemental information from acn 819050: upon inspection of the nose gear and wheel well by maintenance personnel; it was discovered that the nose strut had completely deflated inflight and because of this deflation; the nosewheel did not center correctly when it was retracted; causing it to not be seated correctly in the nosewheel well. The nose gear actually seated against the nose gear doors which prevented the nose gear doors from fully closing. This inability to completely close caused the red 'nose unsafe' indicator to illuminate. Upon further inspection; it was discovered that the nose strut had a leak which allowed the strut to decompress fully to a 0 psi level. The strut was serviced via learjet maintenance specifications; and upon putting the aircraft on jacks; it was discovered that with the nosewheel completely extended; the strut deflated to 15 psi rapidly. The issue is still being worked at this time. Upon further consideration and after careful examination of the maintenance personnel and the results discovered; I believe the emergency declaration and actions of the crew were in the best interest of safety and within all legal parameters. However; looking back on the incident; the only thing that I would have done differently would be not to recycle the gear into the go around up position to prevent any further occurrences and to ensure that the gear are in fact 'down and locked' as according to the gear indicators. Overall; I am very satisfied with the crew's performance and believe this was the safest decision to be made at the time and with the information that we had.

Title: A LR35A nosewheel strut deflated after takeoff causing the nosewheel to retract turned thus preventing a safe nose gear up indication in flight. An emergency was declared followed by a normal landing at a diversion airport with Lear maintenance.

Narrative: On takeoff roll; a steering anomaly was encountered and the takeoff was aborted. Another attempt was made ending in an aborted takeoff. The passenger was dropped in the FBO and I inspected the nose gear and noticed no abnormality. The other pilot has more experience in type and we decided to request a high speed taxi on runway. The test produced no abnormality. We picked up our passenger and departed with no indication of malfunction. The right seat pilot performed the takeoff. During climb; we retracted the gear and noticed an unsafe light for the nose gear. We recycled several times and each time the gear locked down with 3 green lights and no red lights. After reaching a safe altitude; we declared an emergency and elected to land at ZZZ although our takeoff alternate was ZZZ2. We made that decision because there is a Lear service center at ZZZ. The flight was uneventful. We encountered light rime ice during the flight. Upon arrival at ZZZ; we performed a low approach and the Tower said the gear 'appeared down.' This was only a precautionary measure because we had 3 green lights indicating that all wheels were down and locked. We held the nose off the runway as long as possible and upon contact we felt a slight jerk to the left. The landing was normal otherwise. We engaged the electric steering and taxied to the ramp with no issues. The Tower declined to have us write a report and the only information taken was by the fire crew. Upon inspection; the nose strut was found to be completely deflated. During preflight in ZZZ1; the nose strut was inflated within limits. The Maintenance crew determined that the loss of directional control was due to the low strut and the red unsafe indication was due to the nosewheel being wedged at an angle in the wheel well not allowing the nose doors to completely close. Given the nature of the problem; I do not believe that we could have forecast the results we had Supplemental information from ACN 819050: Upon inspection of the nose gear and wheel well by Maintenance personnel; it was discovered that the nose strut had completely deflated inflight and because of this deflation; the nosewheel did not center correctly when it was retracted; causing it to not be seated correctly in the nosewheel well. The nose gear actually seated against the nose gear doors which prevented the nose gear doors from fully closing. This inability to completely close caused the red 'nose unsafe' indicator to illuminate. Upon further inspection; it was discovered that the nose strut had a leak which allowed the strut to decompress fully to a 0 PSI level. The strut was serviced via Learjet maintenance specifications; and upon putting the aircraft on jacks; it was discovered that with the nosewheel completely extended; the strut deflated to 15 PSI rapidly. The issue is still being worked at this time. Upon further consideration and after careful examination of the Maintenance personnel and the results discovered; I believe the emergency declaration and actions of the crew were in the best interest of safety and within all legal parameters. However; looking back on the incident; the only thing that I would have done differently would be not to recycle the gear into the go around up position to prevent any further occurrences and to ensure that the gear are in fact 'down and locked' as according to the gear indicators. Overall; I am very satisfied with the crew's performance and believe this was the safest decision to be made at the time and with the information that we had.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.